1. Field of the Invention
The present invention proposes to answer a need which has been born and has developed in parallel with the intensification of communications over the entire surface of the terrestrial globe. Reception at home of information coming from all points on the globe, whether by private means, such as fax or telephone, or by public means, such as through television, is more and more rapid and intense. On the other hand, the ease of movements over distances covering a large proportion of the circumference of the earth is continually increasing. These realities today require, on the part of an increasing number of persons, quick knowledge of conditions (time of day or night, date, season, distances) which characterize a given place situated at a great distance with respect to the place where the person is located.
The invention aims to answer this need by creating an instrument for measuring time which gives the required information instantaneously, thanks to a synoptic display, and in a practical and manageable form. This horometric device can be achieved in a multiplicity of different forms, for example as a clock, pendulum clock, table clock or wall clock, or as a device for screen display, etc. For simplification, the general term "clock" will be used in the rest of this specification.
2. Description of Related Art
Several constructions for horological devices are already known having a substrate with a geographic representation of the surface of the globe, a time guide-mark and means to display a marking representing the line of movement of the twilight or crepuscule, these components being driven by a motor assembly, the relative movements simulating the movements of the earth with respect to the sun.
German patent application DOS 2 018 727, published in 1971, suggests using as a substrate a spherical shell supported by a coaxial arbor at the line of the poles and, as a means to display the crepuscular line, a second hemispherical, transparent or tinted shell, partially surrounding the substrate, pivoting about an axis which is perpendicular to the line of the poles and passing through the center of the globe. The time guide-mark is a ring, fixed or capable of slight oscillating motion, which surrounds the substrate at the level of the equator or in the vicinity of the south pole.
However, the teachings of this publication only partially answer the needs mentioned above: on the one hand, the clock is conceived mainly as a horological instrument measuring sidereal time and not mean solar time; on the other hand, the design of the time guide-mark and its cooperation with the geographical representation borne by the substrate do not permit an easy reading of the local time at any moment in all the time zones. Lastly, the driving mechanisms provided are relatively complex.
Another prior art document, the French patent FR 1.411.022, proposed a similar construction in 1965 in which the substrate has the shape of a cylindrical body bearing a geographical representation of the terrestrial globe of the Mercator type. The means of display of the crepuscular line is a screen, equipped with a lamp, mounted pivoting on the interior of the substrate.
Also in this case the time guide-mark is a simple ring situated at the base of the substrate, which impedes easy reading of the local time at any point of the geographic representation, and the motor means necessary in the case where an entirely automatic and regulated drive must be provided appear complicated.
The patent application EP 0 441 678, published in 1991, also relates to a terrestrial globe mounted so as to simulate the movements of the earth with respect to the sun. However, this design, which includes relatively complex mechanisms, is mainly conceived so as to indicate sidereal time, and its time guide-mark does not allow an easy reading of local time.
The result of this analysis is that in order to answer the current needs, defined at the beginning, it is necessary to create a horometric device which has a maximum of quality with respect to the following three points of view:
Easy reading of local time, PA1 Clear simulation of the real movements in the solar system, PA1 Simplicity of construction.